System for digital transfer printing on light or dark textile substrates and transfer method

Abstract

The present invention relates to a system for printing and transferring digital images onto different substrates, especially textiles, on light or dark backgrounds, with innovative effects, very good coverage, a smooth feel, high definition, good elongation and excellent resistance to washing. To achieve this result, the system comprises four elements: transfer paper; digital inkjet printing inks (CMYK); transparent base ink; and powdered adhesive with colours and effects. Furthermore, the present invention comprises a method for transferring said images onto said items.

Description

[0001] DIGITAL TRANSFER PRINTING SYSTEM ON LIGHT OR DARK TEXTILE SUBSTRATES AND TRANSFER PROCESS

[0002] FIELD OF INVENTION

[0003] The present invention relates to the field of image transfer onto articles; more specifically, the present invention relates to a system for printing and transferring digital images onto different substrates, especially textiles, on light or dark backgrounds, with very good coverage, soft touch, high definition, good elongation, and excellent wash resistance. To achieve this result, the system comprises four elements: transfer paper; inkjet digital printing inks (CMYK); transparent base ink; and colored and effect-based powder adhesive. Additionally, the present invention comprises the process for transferring said images onto said articles.

[0004] BACKGROUND OF THE INVENTION

[0005] Given the significant developments in the field of digitalization, the textile printing industry is continually striving to leverage the advantages of this digital technology for direct and indirect textile printing. Thus, among the most developed and widely used digital textile printing techniques are:

[0006] Sublimation: This is an indirect printing method in which images are digitally printed on paper with sublimable disperse dye-based inks and then transferred to textiles using heat and pressure. However, this method is only applicable to light-colored fabrics with a high polyester content.

[0007] DTG (direct-to-garment) transfer: This is a direct printing method where the ink is applied directly to the garment using a digital printhead or printer, without the need for intermediate supports such as paper or textile vinyl. Its main limitations are the high cost of the inks used with this technique, the slow printing process, and the pretreatment required for the textile to be printed.

[0008] Printed and unprinted heat-transfer textile vinyls: This is an indirect printing method, where a vinyl material has an adhesive that, when heated, activates and adheres to the fabric. This vinyl can be digitally printed and cut into designs, shapes, and letters. Its main limitations are the slowness and technical complexity of the process, since, to generate the images for transfer, it is necessary to manually remove the parts that are not part of the design.

[0009] DTF (Direct to Film) Transfer: This indirect printing method, where an image is digitally printed onto a special synthetic substrate (a carrier), uses a RIP (raster image processor) software that manages the printing order of the colored inks and an additional white ink, so that the printed colors of the image are covered with an overlay of white ink. After spreading and curing a colorless powder adhesive over the printed image, the same image is transferred onto a light or dark textile substrate. This technique frequently results in blockages of the piezoelectric heads in the digital printers used. This, in turn, causes frequent machine downtime and reduces the lifespan of the heads.This is primarily due to the fact that the white background inks used to provide coverage during substrate transfer have a strong tendency to settle and form lumps. This is because they must be formulated with resins and have low viscosity to be injected into the printheads. Their components include white inorganic pigments with a high tendency to settle (high specific gravity). To counteract these problems, this technique proposes routine cleaning protocols for piezoelectric printheads and the implementation of white ink recirculation systems in printers. However, this has the disadvantage of high ink consumption, which decreases productivity and significantly increases costs.

[0010] In this way, the DTF method can be considered one of the closest to the present invention, making it clear that the present invention overcomes the problems that said DTF method entails. Thus, in the state of the art there are a plurality of disclosures related to this type of inventions, among which is document US20200347253A1, which discloses an article, such as a garment made with a textile fiber product, that carries a transferred printed image, maintaining its essential properties, such as texture, to the maximum possible. Likewise, this invention teaches a manufacturing process for said article; a transfer material to carry out the transfer; and a material to obtain the transfer material.The transfer material is produced by forming a hot-melt adhesive layer portion in specific post-printing areas on a specified side of a substrate so that it can be removed from the substrate, forming a printed image layer to display a desired image on the adhesive layer portion by plateless printing. The adhesive layer portion and the printed image layer of said transfer material are heated and pressed against the subject article to achieve fusion bonding of the adhesive layer portion with the subject article, thereby affixing the adhesive layer portion and the printed image layer to the subject article upon cooling.

[0011] However, this invention does not mention selective transfer to the substrate; the entire adhesive film is transferred. Where there is no image, the transferred film is transparent. Likewise, since this film is transparent, the transfer is not applicable to dark substrates. Furthermore, this document indicates that the transfer occurs by fusion, not by the inclusion of an adhesive powder that adheres to the substrate. Said adhesive powder comprises colors, preferably white and effects, and is not transparent.

[0012] Another related disclosure is disclosed in JP5656168B2, which relates to a printing method, a transfer material and an ink jet discharge device, and more particularly, to a transfer printing method, and a transfer material and an ink jet discharge device used in the printing method.

[0013] However, this invention mentions that at the time of printing the image, the areas not belonging to the drawing are also coated with UV-curing inks, such that when the transfer is made, the areas of the coating that do not belong to the image are not transferred to the substrate, a fact that is far from the present invention. In this invention, the adhesive is located on the substrate where the image is printed, not in the form of powder that covers the freshly printed, wet print layer.

[0014] On the other hand, there is document US11577536B2, which allows an image to be formed on a transfer medium comprising a hydrophilic adhesive agent. Any portion of the image that is dimensionally insufficient to permanently adhere the image to the receiving substrate is determined, and a colorless liquid ink comprising water is applied to cover and surround the portion of the image that is dimensionally insufficient to permanently adhere the image to the receiving substrate, receptor substrate. When heat is applied to the image to transfer the image layer to a receiving substrate, the water in the image layer swells the image layer and the hydrophilic adhesive becomes sufficiently tacky to permanently adhere the image to the receiving substrate.

[0015] However, in this document, the inks are dye-based; they do not use water-based pigment-based inks printed by piezoelectric printheads. In this document, adhesion to the substrates where the transfer is made is based on a principle of increased tack due to the wetting provided by the inks when the carrier substrate is printed. Since dyes are used, this method only works for transfers onto clear substrates; its components do not contain a powder adhesive that generates effects or coatings, which would cover the freshly printed, wet print layer. This system uses the adhesive resin on the support where the image is printed.

[0016] Likewise, there is document US9399362B1 which relates to a method for transferring an image to an article using a heat transfer assembly having a support layer and an image transfer layer, wherein the image transfer layer contains a binder, an ink receptor, and a film-forming hydrophilic blocking agent. When an aqueous ink composition is used to print an image on the upper surface of the transfer assembly, the blocking agent is disturbed in the image areas but not in the non-image areas such that when the image is transferred to a substrate by the application of heat and pressure, substantially all of the binder in the non-image areas remains in the transfer assembly.

[0017] However, this invention has the disadvantage that the carrier support coating is provided by at least two layers. The outermost layer serves as a blocking agent for the carrier support coating when transferring it to the desired substrate. This means that only the carrier support coating is transferred in the areas that are part of the design. In the areas where the water-based ink, which can be pigment or dye, falls, the blocking layer dissolves, and the ink is absorbed by an inner layer containing a thermofusible resin.

[0018] For its part, document US20230118044A1 teaches a process for producing a digitally printed heat transfer, the process comprising the steps of: 1) obtaining a substrate having a release layer; 2) applying a primer suitable for electrophotographic toner to the release layer; 3) digitally printing electrophotographic toner to define a graphic within a defined region of a substrate that includes both printed and non-printed areas within that region; 4) digitally printing a tacky viscoelastic binder in correspondence with the printed areas of the digitally printed graphic; 5) applying a polyurethane-based powder adhesive to the defined region of said substrate; 6) removing loose powder adhesive that does not adhere to the defined regions of said graphic; and 7) fusing and bonding the adhesive to the digitally printed graphic. The binder precisely fixes the adhesive powder to the printed graphic areas.The result is then cooled to set the image and use it as a heat transfer.

[0019] However, this invention has the disadvantage that it is based on an electrophotographic toner system and does not use water-based pigment-based inks printed by piezoelectric printheads. Additionally, the carrier medium consists of several layers of coating. This is laser printing, meaning it does not use a piezoelectric printhead, so water-based digital inks are not used.

[0020] Finally, there is document US8350880, which relates to a heat image transfer system and a method for using it. The heat image transfer system includes a heat transfer sheet and an activator ink. The heat transfer sheet and activator ink are specially formulated so that only the areas of the heat transfer sheet on which the ink has been printed become adhesive under heat transfer conditions.This effect can be achieved by designing the sheet to include an ink-receptive coating whose melting temperature is higher than that typically encountered during normal heat transfer conditions and by formulating the activator ink to include a plasticizer that, when printed onto the ink-receptive coating, reduces the melting temperature of the ink-receptive coating sufficiently so that the modified melting temperature falls within the temperature range encountered during heat transfer.

[0021] However, this patent does not include among its components a colored and effect-based powder adhesive that is spread over the printed image on the carrier support, so that the transferred images are opaque on dark textile substrates or have a wide variety of effects.

[0022] From the information disclosed in the state-of-the-art documents, it can be clearly seen that the problems posed must be solved in order to obtain a method for transferring images made up of digital printing that does not use white digital background inks with a strong tendency to sedimentation and lump formation, where said method includes colored and effect powder adhesive that, in addition to giving the transferred image a white color, has the alternative of including different effects, such as: metallic (gold, silver, etc.), fluorescent, pearlescent, spongy (chemical foaming agents or with expandable microspheres), migration control agents, among others. Where, in addition, the image transfer is selective.Furthermore, the selective transfer of the image to the textile substrate is based on the thermal fusion of the powder adhesive spread over the printed design on the carrier support and the selective plasticization of thermoplastic resins present in the coating, thanks to the application of a layer of transparent base ink applied to the image to be transferred at the time of digital printing (selective transfer of the coating from the carrier support). Wherein, the surprising technical effect is that this invention makes it possible to develop digitally printed images with totally new and unprecedented effects. Additionally, technical problems are overcome by eliminating the digital white inks that until now were necessary to generate coverage on textile substrates.

[0023] In accordance with the foregoing, it is clear that there is a need in the state of the art to offer a digital transfer printing system on light or dark textile substrates that includes a colorless transparent base ink that is digitally printed, simultaneously with the CMYK colored inks on a coated paper and subsequently covered with a powder adhesive that melts for the transfer, where said transparent base is a fluid ink without sediments that prevents the clogging of the printer heads while interacting with the transfer paper to perform a selective transfer, where the powder adhesive coating includes a composition that favors the transfer of the image printed on the coated paper to dark or light textile substrates or other materials to which the powder adhesive has affinity, for example non-woven substrates, wood, cardboard and PVC tarps, etc.any type of material, while ensuring elasticity and resistance to washing.

[0024] BRIEF DESCRIPTION OF THE INVENTION

[0025] The present invention consists of a novel digital printing method belonging to the field of indirect printing, preferably for printing on textile substrates. By applying different principles and elements, an original approach is made to eliminate the disadvantages of the previously described printing techniques and also to generate novel and unprecedented colors and effects in printed images. Among the elements of this invention are: the transparent base ink, which is a colorless ink for digital printing that covers both the areas where the CMYK colors (cyan, magenta, yellow, and black) of the image are printed, as well as the reserved areas of the design so that its color or effect is provided by a powder adhesive that is subsequently added to the image.This printing method is achieved through RIP (Raster Image Processor) software, which manages the printing order of the CMYK and colorless inks. This transparent base ink is characterized by not containing the aforementioned white inorganic pigments in the DTF printing method, thus avoiding sedimentation problems that could clog the piezoelectric heads. Another element of this invention is the colored and effect powder adhesive, which is trapped over the entire design area when spread over the wet printed image area (Figure 3).This adhesive has the function of generating color, coverage, elasticity, adhesion and special effects on the textile substrate to which the image is transferred. On the other hand, there is the coated transfer paper (Figure 1), designed to receive images with pigment-type digital printing inks, allowing these images to be transferred to a textile substrate, by means of a receiving base.

[0026] In this way, the present printing system and process allow images to be transferred onto textile substrates based on synthetic or natural fibers, light or dark, with perfectly defined contours, stretchability, true tone, resistance to washing and rubbing required for textile garments, with a soft finish and new and innovative colors and effects. (Figure 7).

[0027] DESCRIPTION OF THE FIGURES

[0028] The present invention is understood more clearly from the following figures, which show the components and results associated with the present development, as well as the novel characteristics with respect to the state of the art, where the figures are not intended to limit the scope of the invention, which is only given by the attached claims, where:

[0029] Figure 1 shows the transfer paper (1) of the present invention. Figure 2 shows the transfer paper (1) on which the transparent base ink (3) has been digitally printed, superimposing itself on the areas of the image that are printed with CMYK colors and directly moistening the transfer paper in the areas reserved for the white color of the image (123) which can also be understood as areas reserved so that their color or effect is provided by the colored and effect powder adhesive according to the design of the image being printed.

[0030] Figure 3 shows the colored and effect powder adhesive (4) spread over the printed wet layer of transparent base ink (3), according to the present invention.

[0031] Figure 4 shows the dry-to-the-touch film (34) composed of the colored and effect powder adhesive (4) and the transparent base ink (3) after the curing process, according to the present invention.

[0032] Figure 5 shows the transfer process on a substrate with the help of a heat press (5) according to the present invention.

[0033] Figure 6 shows the areas of the paper coating transferred to the textile substrate corresponding to the areas of the image printed in CMYK colors and to the areas of the image corresponding to the white color (123), which can also be understood as areas reserved so that their color or effect is provided by the colored and effect powder adhesive according to the design of the image being printed. It also shows the area of ​​the paper coating that is not transferred to the textile substrate and that is not part of the transferred image.

[0034] Figure 7 shows the final arrangement of the transferred film on the textile substrate. The CMYK colors of the image are surrounded by a heat-fused layer composed of the paper coating, the colored and effect-based adhesive powder, and the colorless ink for digital printing.

[0035] Figure 8 shows the result of the transfer, where the images are transferred onto textile substrates based on synthetic or natural fibers, light or dark, with their contours perfectly defined, elongable, faithful in tone, resistant, with a smooth finish and novel colors and effects, in accordance with the present invention.

[0036] DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention relates to a digital transfer printing system on light or dark textile substrates, characterized in that it comprises: a transfer paper (1); digital inkjet printing inks (2); transparent base ink (3) and colored and effect powder adhesive (4), wherein the transfer paper includes a coating layer (12); wherein said paper (1) receives a digital print made by means of RIP software, Raster image processor, which manages the printing order of the inks in an inkjet printer, such that both the areas of the image where the CMYK colors (cyan, magenta, yellow and black) are printed, as well as the areas in the image design that correspond to the color white, (because they are reserved so that their color or effect is provided by the colored and effect powder adhesive), are superimposed by a layer of the transparent base ink.Subsequently, said wet layer receives the colored and effect powder adhesive (4), then heat is supplied to the printed image, to melt the powder adhesive that was impregnated in the image, at temperatures between 160°C and 180°C, between 10 and 40 seconds forming a cured film, in this way the powder adhesive retained in the image melts leaving a dry to the touch film (34) on the printed image, allowing the storage or subsequent transfer of the image onto a preferably textile substrate.

[0038] Transfer paper:

[0039] The transfer paper (1) of the present invention consists of a coated paper for the transfer of images onto preferably textile substrates that has a coated layer similar to digital printing inks. An example of transfer paper is taught in the invention CO-NC2019 / 0008859, in this way said paper must include elements such as water-soluble polymers, fillers, resins or thermoplastic polymers, agglomerating polymers, release agents and preservatives, which together with the other elements included in the present digital transfer printing system on textile substrates achieves an adequate transfer of the image.

[0040] Colored digital inkjet printing inks:

[0041] The digital inkjet printing inks (2) used in this invention are pigment-based inks, which are specially formulated to minimize clogging of the print heads. These inks are characterized by not including resins in their ingredients, which tend to form a film and increase the probability of generating blockages in the print heads. These inks comprise, among their ingredients, deionized water between 20% and 80%, organic pigments between 3% and 15%, preservatives between 0.1% and 0.2%, drying retardants between 5% and 30% and wetting agents between 1% and 5%.

[0042] Deionized water used in color printing inks should preferably have a maximum conductivity of 75 microsiemens to prevent deterioration of the piezoelectric heads due to corrosion.

[0043] The organic pigments that make up these printing inks can include various types of pigments, specifically, phthalocyanine pigments, quinacridone pigments, monoazo pigments, diarylide pigments, pyrazolone pigments, dizaso condensation pigments, and polycyclic pigments. In their dispersion, they must have a particle size of less than 200 nanometers, preferably less than 80 nanometers.

[0044] The drying retardants that make up these colored digital printing inks can be selected from water-soluble materials such as ethylene glycol, 1,3 propanediol, and 1,4 butanediol. 1,4 cyclohexanedimethanol. 1,5 pentanediol, 1,6 hexanediol, 1,8 octanediol. 1,2 propanediol, propane-1,2,3-triol, 1,2 butanediol, 1,3 butanediol. 2,3 butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol with average molecular weight of 200, 300, 400, 600, 900, 1000, 1500 and 2000.

[0045] The preservatives that make up these color digital printing inks can be selected from the group of chloromethylisothiazolinone derivatives, which have a broad spectrum of activity, controlling bacteria (both gram-negative and gram-positive) and fungi, such as yeast and mold. They do not contain formaldehyde and are approved by the FDA for use in adhesives and paper coatings due to their low toxicity. This microbicide is non-toxic at the recommended use levels in its final formulation.

[0046] The wetting agents that make up these colored digital printing inks can be selected from the group of ethoxylated acetylene diols 2,5,8, ll-Tetramethyl-6-dodecyl-5,8-diol ethoxylated; sulfosuccinates such as dioctyl sodium sulfosuccinate, sodium dibutyl sulfosuccinate, sodium diisopropyl sulfosuccinate; siloxane-based gemini surfactants; fluorinated surfactants, organosilicones; surfactants based on 1-octylpyrrolidin-2-one pyrrolidones. By reducing the surface tension of the inks, wetting agents improve the wetting of the coated transfer paper that is digitally printed. Additionally, they help control drop formation in the printer heads.

[0047] Transparent base ink:

[0048] The transparent base ink (3) of the present invention consists of a colorless water-based ink that can comprise a 100% aqueous system or an oil-in-water emulsion, wherein said transparent water-based ink is characterized in that it comprises: deionized water between 20% and 80% by weight; drying retarding agent between 10% and 40% by weight; pH stabilizer between 0.5% and 4% by weight; preservatives between 0.1% and 3% by weight; emulsifying agents between 0.5% and 4% by weight; wetting agents between 2% and 20% by weight; optical brightener between 0.5% and 3% by weight and plasticizers with concentrations that are between 5% and 40% by weight.

[0049] The deionized water that makes up the transparent base ink (3) of the present invention should preferably have a maximum conductivity of 75 microsiemens, to avoid deterioration of the piezoelectric heads due to corrosion.

[0050] The drying retarding agents that make up the transparent base ink (3) of the present invention are selected from the group of water soluble materials, such as ethylene glycol, 1,3 propanediol, and 1,4 butanediol. 1,4 cyclohexanedimethanol. 1,5 pentanediol, 1,6 hexanediol, 1,8 octanediol. 1,2 propanediol, propane-1,2,3-triol, 1,2 butanediol, 1,3 butanediol. 2,3 butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol with average molecular weight of 200, 300, 400, 600, 900, 1000, 1500 and 2000.

[0051] The pH regulators that make up the transparent base ink (3) of the present invention are selected from the group of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, triethanolamine, 2-amino-2-methyl-l-propanol, diethanolamine, ethanolamine, where these compounds additionally contribute with emulsifying and humectant properties and seek to achieve a pH between 8 and 9 for the transparent base ink (3).

[0052] The preservatives comprising the transparent base ink (3) of the present invention are selected from the group of chloromethylisothiazolinone derivatives, which have a broad spectrum of activity, controlling bacteria (gram-negative and gram-positive) and fungi, such as yeasts and molds. They do not contain formaldehyde and are authorized by the FDA in adhesives and paper coatings due to their low toxicity. This microbicide is non-toxic at the recommended use levels in its final formulation.

[0053] The emulsifying agents that make up the transparent base ink (3) of the present invention are selected from the group of non-ionic emulsifying agents such as: glycerol esters, such as glycerin monostearate and glyceryl stearate citrate, which form oil-in-water emulsions. Fatty alcohols of different degrees of ethoxylation, of 3, 4, 6, 8, 10 ethylene oxide molecules, such as lauryl alcohol ethoxylated with 10 ethylene oxide molecules, are also an option. Additionally, polyglycerides, which are polymers of glycerin and fatty acids, form oil-in-water and water-in-oil emulsions depending on the degree of polymerization. Likewise, alkanolamides of fatty acids could function, such as lauryl-diethanol amide, oleyl-diethanol amide. Another option is ethoxylated amines, ethoxylated amides.Anionic emulsifying agents are also a very good option, including straight- and branched-chain sodium alkylbenzenesulfonates, straight- and branched-chain alkyl sulfates, and straight- and branched-chain alkyl ethoxy sulfates. Finally, sucrose fatty acid esters, such as sucrose polystearate, form oil-in-water emulsions and have emollient and conditioning properties.

[0054] The wetting agents that make up the transparent base ink (3) of the present invention are selected from the group of ethoxylated acetylene diols 2,5,8, 11-Tetramethyl-6-dodecyl-5,8-ethoxylated diol; sulfosuccinates such as dioctyl sodium sulfosuccinate, sodium dibutyl sufosuccinate, sodium diisopropyl sulfosuccinate; siloxane-based gemini surfactants; fluorinated surfactants, organosilicones; surfactants based on 1-octylpyrrolidin-2-one pyrrolidones. By reducing the surface tension of the transparent ink, the wetting agents improve the wetting of the coated transfer paper that is digitally printed. Additionally, they help control the formation of drops in the printer heads and their coalescence in the printed image.

[0055] The optical brighteners or whiteners that make up the transparent base ink (3) of the present invention are selected from the triazine-stilbene group such as 4,4 diamino 2,2 stilbene disulfonic acid, coumarins such as triazine phenyl coumarin, benzotriazole phenyl coumarin, naphthotriazole phenyl coumarin, bis benzoxazoles, imidazolines, diazoles, triazoles, biphenyl stilbenes. For routine checks of the status of the print head injectors that are carried out by means of an injector test, since this is a transparent ink, an optical brightener is formulated within its components, which under the illumination of a lamp that emits UV light radiation, makes the injector test visible.

[0056] Taking into account compliance with regulations in the textile industry, regarding the permitted limits of phthalates. The following should be selected from the group of plasticizers: those based on aliphatic dicarboxylic acids Dibutyl adipate, Dibutoxy ethyl adipate, Di (2-ethyl hexyl) adipate, Di isooctyl adipate, Diisodecyl adipate, dibutyl sebacate, Butyl benzyl adipate, Di octyl sebacate, they can also be selected from citric acid esters such as Triethyl citrate, tributyl citrate, acetyl tri (n-butyl) citrate, acetyl tri (n-hexyl) citrate. Likewise, esters of alkylsulfonic acids with phenols, benzoates such as propylene glycol dibenzoate, dipropylene glycol dibenzoate, terephthalates such as Di 2 ethylhexyl phthalate (Dotp), trimellitates such as tri 2 ethylhexyl trimellitate (TOTM), triisooctyl trimellitate (TIOTM), triisononyl trimellitate (TINTM) could work.

[0057] One of the functions of the overlay layer of the transparent base ink (3) is to increase the total deposit of the digitally printed ink so that it serves as a wet receptive layer for the colored and effect powder adhesive that is added to the printed image. Specifically, the range of deposit of colored inkjet digital printing inks on coated paper being between 1 and 20 grams per square meter, the deposit of the transparent base ink must be between 20 to 50 grams per square meter, so that a sufficiently thick wet film is generated that has the capacity to receive and retain the colored and effect powder adhesive.

[0058] Likewise, the overlying layer of transparent base ink, mainly through its constituent plasticizers (when they are already part of the cured film with powdered adhesive retained in the image); at the time of transfer onto the textile substrate, they interact by selectively plasticizing the thermoplastic resins present in the paper coating, which ensures that the areas of the paper coating that are not part of the image areas are not transferred to the substrate.

[0059] Additionally, the ingredients that make up the transparent base ink contribute to the elasticity and release capacity of the image transferred from the textile to the body.

[0060] The colored and effect powder adhesive:

[0061] The main function of the colored and effect powder adhesive (4) of the present invention is to promote the transfer of the images printed on the transfer paper (1) to dark or light textile substrates, made of natural or synthetic fibers such as cotton, linen, hemp, silk, wool, polyester, nylon, spandex, acrylic, rayon. Additionally, this adhesive provides colors, effects, adhesion, coverage, elasticity, wash resistance and rub resistance of the transferred images on the textile substrate.

[0062] The colored and effect powder adhesive (4) of the present invention comprises: thermofusible resins between 20% and 80% by weight; white covering pigments between 5% and 50% by weight; foaming agents between 1% and 5% by weight; mineral fillers between 1% and 20% by weight; plasticizers between 0.5% and 20% by weight; thermoplastic resins between 1% and 20% by weight; colored and special effect pigments between 3% and 30% by weight.

[0063] The thermofusible resins that make up the colored and effect powder adhesive (4) of the present invention are selected from the group of ethylene vinyl acetate polymers, in block copolymers styrene isoprene styrene or styrene butadiene styrene, low density polyethylene, polyamides, ethylene acrylic copolymers, polypropylene, phenoxy resins, polyester, polyester amide, polyurethanes, butyl rubber, polyvinyl acetate and its copolymers and paraffin waxes. The thermofusible resin mainly greatly favors the transfer, elasticity and adherence of the image that is transferred to the textile substrate.

[0064] The white covering pigments that make up the colored and effect powder adhesive (4) of the present invention are selected from the group of titanium dioxide in its crystalline forms of rutile and anatase, zinc oxide, lithopone, zinc sulfide and mixtures of barium sulfate and zinc sulfide. The covering pigments basically provide coverage and sharpness to the images that are transferred onto the light or dark textile substrate.

[0065] The blowing agents that make up the colored and effect powder adhesive (4) of the present invention are selected from the group of hydrazines such as 4,4'-Oxybis (benzenesulfonylhydrazide), Diphenylsulfone 3,3 disulfohydrazide, Trihydrazinotriazine, semicarbazides such as P-tolylenesulfonyl semicarbazide, tetrazoles such as phenyltetrazoles, expandable polymeric microspheres, Benzoxazines such as isatoic anhydride and azodicarbonamide.

[0066] The mineral fillers that make up the colored and effect powder adhesive (4) of the present invention are selected from the group of calcined or hydrated aluminum silicate (kaolin), natural or synthetic calcium carbonate, talc, silicates, mica, pyrogenic silicas, microcrystalline silica, diatomaceous silica, synthetic silicas. The mineral fillers must have average diameters between 5 and 20 microns.

[0067] The plasticizers that make up the colored and effect powder adhesive (4) of the present invention are selected from the group of:

[0068] Solids: neopentyl glycol dibenzoate, glyceryl tribenzoate, 1,4 cyclohexane dimethanol dibenzoate.

[0069] Liquids: dibutyl adipate, dibutoxy ethyl adipate, di(2ethylhexyl) adipate, di isooctyl adipate, diisodecyl adipate, dibutyl sebacate, butyl benzyl adipate, di octyl sebacate, they can also be selected from the esters of citric acids such as triethyl citrate, tributyl citrate, acetyl tri (n-butyl) citrate, acetyl tri(n hexyl) citrate. Also working are esters of alkylsulfonic acids with phenols, benzoates such as propylene glycol dibenzoate, dipropylene glycol dibenzoate, terephthalates such as Di 2 ethylhexyl phthalate (dotp), trimellitates such as tri 2 ethylhexyl trimellitate (TOTM), triisooctyl trimellitate (TIOTM), triisononyl trimellitate (TINTM).

[0070] The thermoplastic resins that make up the colored and effect powder adhesive (4) of the present invention are selected from the group of polyvinyl chloride, polyurethane, acrylic, polyethylene, polypropylene, polyester and polycarbonate.

[0071] The coloured and special effect pigments that make up the coloured and effect powder adhesive (4) of the present invention are selected from the group of organic pigments based on phthalocyanines, benzidines, pearl pigments, mirellas, phosphorescent pigments, fluorescent pigments, thermochromatic, photochromic, metallic pigments of different colours such as silver, gold, copper, etc.

[0072] The present invention further comprises a digital transfer printing process on light or dark textile substrates characterized in that it comprises the following stages: a. Printing the image on the transfer paper (1), by means of a piezoelectric head printer loaded with digital printing inks (CMYK) inkjet (2) and transparent base ink (3). In a desired embodiment, a printing software (RIP) is used, which manages the quantity and printing mode of the inks.

[0073] The image is printed in mirror mode, where, as the CMYK colors are printed, the transparent base ink (3) is printed on said layer of colors, forming a translucent and shiny layer that covers the entire area of ​​​​the image. The transparent base ink, in addition to covering the printing area of ​​​​the CMYK inks, is also printed in the areas where the white color of the image goes according to the design. In those areas where the white color is, only the translucent layer of transparent base ink is printed. b. Once the print leaves the printer, the colored and effects powder adhesive (4) is applied to the newly printed wet image.

[0074] It is necessary to ensure that the colored and effects powder adhesive (4) achieves homogeneous coverage, since said colored and effects powder adhesive must be retained by the wet layer printed with transparent base ink. Once the colored and effects powder adhesive (4) has been applied, any excess that is outside the printed image must be removed. c. The image coated with the colored and effects powder adhesive (4) is cured by supplying heat in an oven or with a heat gun between 160 ° C and 180 ° C for between 10 and 40 seconds. The white color and the effects on the image are obtained with the addition of the colored and effects powder adhesive. d. The transfer paper from the previous paragraph is placed, with the printed image in direct contact with the substrate where it will be transferred and is subjected to thermal pressing between 150°C and 200°C for 10-20 seconds at a pressure between 2.1 and 6.3 kgf / cm2 (30 to 90 Lbf / in 2). e. Remove the garment or substrate and allow to cool completely. f. Peel back the transfer paper to reveal the image transferred to the substrate.

[0075] Optionally, after curing, the transfer paper can be stored for later transfer.

[0076] In one embodiment, in literal b. after 15 to 20 seconds of applying the coloured and effect powder adhesive (4), the powder adhesive that did not come into contact with the image must be removed, preferably by mechanical or manual vibration of the printed paper while it is in a vertical position or by suction with the paper in a horizontal position.

[0077] In one embodiment, in literal d. the transfer paper from the previous literal is placed on the substrate where it will be transferred and is subjected to thermal pressing in a calender at 160°C for 15 seconds at a pressure of 4.2 kgf / cm2.

[0078] Thus, the system and process of the present invention is applicable in desktop printers (Epson L805, L8050), where, in a desired embodiment, said printer must have at least 6 injection channels, where, 4 channels are intended for the injection of CMYK inkjet digital printing inks (2), and 2 channels are intended for the injection of transparent base ink (3). On the other hand, the system and process of the present invention is applicable in medium and large format roll printers in which some injection channels can be dedicated to CMYK colors and other injection channels to the printing of transparent base ink. Integrated printer, powder applicator and curing oven equipment can be used.

[0079] A higher quantity of transparent base ink is required in proportion to digital printing inks (CMYK), in order to overcome the absorption capacity of the paper, since the transparent base ink must guarantee the retention of the colored and effect powder adhesive, which through its ingredients interacts with the components of the paper and the transparent base ink to make the transfer of the image to the textile substrate possible.

[0080] Examples:

[0081] The following examples are given by way of illustration, but should not be construed as a limitation of this invention.

[0082] Example 1

[0083] In order to obtain a printed image with sharp and covering colors on a black cotton fabric, an image transfer paper was digitally printed that has a coating such as that described in the invention CO-NC2019 / 0008859, where said printing is carried out using a RIP software, Raster image processor, (Raster image processor) on a small format Epson L805 desktop printer, with 4 channels that were used for the injection of CMYK inkjet digital printing inks (2), and 2 channels that were used for the digital injection of a transparent base ink (3). Where the image resolution was 1440 * 720 dpi (dots per inch).Where the transparent base ink has the following composition: deionized water 64.2% by weight, 1,3 propanediol 10% by weight, 1,6 Hexanediol 10% by weight, 2-amino-2-methyl-l-propanol 0.3% by weight, methyl isothiazolinone 0.1% by weight, PEG 20 sorbitan monooleate (Tween 80) 1% by weight, Di 2 ethylhexyl phthalate (Dotp) 12% by weight, Di (2-ethyl hexyl) adipate 2% by weight, benzotriazole phenyl coumarin 0.2% by weight and l-octylpyrrolidin-2-one 0.2% by weight. Where the deposit of the CMYK colored inks on the transfer paper was on average 10 grams per square meter and that of the transparent base ink was 30 grams per square meter. Where the printing of the transfer paper was managed in such a way that the areas of the image that were printed with CMYK colored inks and the areas of the image reserved for their color or effect to be given by a powder adhesive, were superimposed by a translucent and shiny layer of the transparent base ink (3).Where immediately after the transfer paper was printed, a white powder adhesive (4) was spread manually over the wet image, which has the following composition: a thermofusible polyester amide resin at 47.7% by weight with a particle size of 10 to 80 microns with a melting range between 105 ° C and 130 C ° and a melt index between 25-30 grams / 10 minutes, an azodicarbonamide sponge agent with 0.3% by weight, a calcium carbonate mineral filler with an average diameter of 2 microns of 5% by weight, a solid glyceryl tribenzoate plasticizer with 10% by weight, a white rutile grade titanium dioxide pigment with 30% by weight, a thermoplastic resin with 7% by weight.Where after 20 seconds of spreading the powder adhesive on the printed paper, this was placed in a vertical position and by means of manual vibration, the powder adhesive that did not come into contact with the image was removed, then the image coated with the white powder adhesive (4) was cured by supplying heat by means of a heat gun, placed over the image at a distance of 15 cm and adjusting its power in such a way that temperatures between 160 ° C and 180 ° C were reached for a time of 40 seconds. Where after 30 minutes in a heat press, the black cotton fabric was placed in contact with the face of the transfer paper where the image was printed. Subsequently, a thermal pressing was carried out, such that the black fabric and the transfer paper were subjected to a pressure of 6.3 kgf / cm2 (90 Ibf / in2) and a temperature of 170 ° C for 20 seconds.The black fabric was then removed from the heat press along with the transfer paper, the fabric and transfer paper were left to cool for 5 minutes before removing the transfer paper from the black fabric, finally it was possible to verify that a sharp, covering image was obtained, with a soft, elastic and resistant finish on the black cotton fabric.

[0084] Example 2

[0085] The objective is to obtain a printed image of fluorescent colors on a light blue cotton fabric. For this, an image transfer paper is used that has a coating such as that described in the invention CO-NC2019 / 0008859, which is digitally printed using RIP software, Raster image processor, on a medium-format printer, with 1 Epson TFP reference piezoelectric print head with six channels and a speed of 7 square meters per hour, with a resolution of 360 * 1800 dpi (dots per inch). With 4 channels that were used for the injection of CMYK inkjet digital printing inks (2), and 2 channels that were used for the digital injection of a transparent base ink (3).Where the printer is coupled to a module to apply the powder adhesive automatically, this system performs the function of applying or spraying the adhesive, removing the excess and heat-setting the enlargement, cooling it and then rolling it up according to the paper format, for this application the transparent base ink has the following composition: deionized water 58% by weight, ethylene glycol 15.3% by weight, triethanolamine 0.2% by weight, Methyl isothiazolinone 0.1% by weight, PEG 20 sorbitan monooleate (Tween 80) 1% by weight, acetylated tributyl citrate 25% by weight, benzotriazole phenyl coumarin 0.2% by weight and l-octylpyrrolidin-2- one 0.2% by weight. Where the deposit of CMYK colored inks on the transfer paper was on average 14 grams per square meter and that of the transparent base ink was 35 grams per square meter.Where the printing of the transfer paper was managed in such a way that the areas of the image that were printed with CMYK colored inks and the reserved areas of the image so that their color or effect was given by a powder adhesive; were superimposed by a translucent and shiny layer of the transparent base ink (3).Where immediately after the transfer paper was printed, the paper passed to a module for applying the fluorescent pink powder adhesive, where it was applied and the excess was removed and heat-set at a temperature of 160 °, the composition of the adhesive was as follows: a polyurethane thermofusible resin at 56.2% by weight with a particle size of 10 to 80 microns, an azodicarbonamide blowing agent with 0.3% by weight, a kaolin mineral filler of 5% by weight, a solid plasticizer neopentyl glycol dibenzoate with 1.5% by weight, a rutile grade titanium dioxide pigment with 10% by weight, a fluorescent pink pigment with 20% by weight, a PVC thermoplastic resin with 7% by weight. Where 24 hours later in a Supra 170 calender, the light blue fabric was placed in contact with the side of the transfer paper where the image was printed.Subsequently, a heat pressing was carried out at a speed of 5 meters per minute, such that the light blue fabric and the transfer paper were subjected to a pressure of 6.3 kgf / cm2 (90 I bf / in2) and a temperature of 170 ° C., then the light blue fabric was removed from the calender, along with the transfer paper. Where the fabric and the transfer paper were left to cool for 10 minutes, before removing the transfer paper from the light blue fabric, then it was possible to verify that a digitally printed image was obtained with a totally novel and unprecedented fluorescent finish. Additionally, the transferred digital image had vivid colors and a clear appearance, covering, with a soft, elastic and resistant finish.

[0086] Example 3

[0087] In order to obtain a printed image of pearly highlights that additionally has sharp and covering colors on a dark blue fabric, an image transfer paper that has a coating such as that described in the invention CO-NC2019 / 0008859 was digitally printed using RIP software, Raster image processor, on a small format Epson L805 desktop printer, with a DX5 reference piezoelectric print head. With 4 channels that were used for the injection of CMYK inkjet digital printing inks (2), and 1 channel that was used for the digital injection of a transparent base ink (3). Where the image resolution was 1440 * 720 dpi (dots per inch). Wherein the transparent base ink has the following composition: deionized water 64.2% by weight, 1,3 propanediol 10% by weight, 1,6 Hexanediol 10% by weight, 2-amino-2-methyl-l-propanol 0.3% by weight, methyl isothiazolinone 0,1% by weight, PEG 20 sorbitan monooleate (Tween 80) 1% by weight, Di 2 ethylhexyl phthalate (Dotp) 12% by weight, Di (2 ethylhexyl) adipate 2% by weight, benzotriazole phenyl coumarin 0.2% by weight and l-octylpyrrolidin-2-one 0.2% by weight. Where the deposit of the CMYK colored inks on the transfer paper was on average 8 grams per square meter and that of the transparent base ink was 35 grams per square meter. Where the printing of the transfer paper was managed in such a way that the areas of the image that were printed with the CMYK colored inks and the areas reserved from the image so that their color or effect is given by a powder adhesive, are superimposed by a translucent and shiny layer of the transparent base ink. Where immediately after the transfer paper was printed, a pearlescent powder adhesive was manually spread over the wet image,which has the following composition: a thermofusible polyurethane resin at 73.9% by weight with a particle size of 0.5 to 80 microns, an azodicarbonamide sponge agent with 0.1% by weight, a pyrogenic silica filler with 2% by weight, a liquid plasticizer of propylene glycol dibenzoate with 2% by weight, a pearlescent pigment with particle sizes in a range of 15 to 150 microns with 20% by weight and an acrylic thermoplastic resin with 2% by weight, after 20 seconds of spreading the powder adhesive on the printed paper, this was placed in a vertical position and by means of manual vibration, the powder adhesive that did not come into contact with the image was removed then the image coated with the pearlescent colored powder adhesive (4) was cured by supplying heat by means of a heat gun,placed over the image at a distance of 15 cm and adjusting its power so that temperatures were between 160°C and 180°C, for a time of 40 seconds, 30 minutes later in a heat press, the dark blue fabric was placed in contact with the face of the transfer paper where the printed image is. Where a heat pressing was carried out, such that the dark blue fabric and the transfer paper were subjected to a pressure of 6.3 kgf / cm2 (90 Ibf / in2) and a temperature of 170°C for 20 seconds, then the dark blue fabric was removed from the heat press along with the transfer paper. Where the fabric and the transfer paper were allowed to cool for 5 minutes before removing the transfer paper from the dark blue fabric, then it could be seen that a new and totally novel image with pearly highlights was obtained. Additionally covering, with a soft, elastic and resistant finish on the dark blue fabric.,

[0088] In one embodiment, image transfer can be applied to other rigid or flexible substrates that have thermoplastic affinity or are porous and allow the images of the system of the present invention to be anchored by heat and pressure. Some examples include porous surfaces such as wood, cardboard, or thermoplastic surfaces such as synthetic leather, acrylic sheets, plastic containers, among others.

[0089] In one embodiment, the system of the present invention can be used in desktop printers or in medium- and large-format printers with a piezoelectric print head. Some print head examples include: Epson F1440, 13200-Al / 11600-Al, S3200-A1, S3200-A3, DX4, DX5, and DX7.

[0090] The colored and effect powder adhesive is preferably white; however, in other embodiments, it may have other colors and special effects, such as gold, silver, fluorescent, pearlescent, transparent, embossed, or migration control agents. Unique special effects and colors are only achieved with the printing system and process disclosed in the present invention.

[0091] Advantages:

[0092] The set of elements taught in the system described previously allows to obtain the following technical effects:

[0093] • The CMYK inkjet printing inks and clear base inks of the present invention do not cause printhead clogging. This allows for high printer stability and productivity, while also saving costs.

[0094] • Significant reduction in machine downtime caused by blockages in the piezoelectric heads used in printers.

[0095] • This printing system has excellent color development and a good transfer system without requiring cutting equipment.

[0096] • Wide color gamut and excellent image resolution.

[0097] • Versatility of use.

[0098] • High-quality prints, excellent feel, durability, and high definition. • Low environmental impact, free of substances harmful to the environment and human health.

[0099] • Multiple special effects.

[0100] • Covering on textiles with light or dark backgrounds, based on natural or synthetic fibers.

[0101] • Adhesion to different substrates.

[0102] • Improves elongation capacity.

[0103] • Improves strength and solidity.

[0104] • Control of dye migration.

[0105] • The ease of handling the technique that allows high productivity.

[0106] • Agility in garment customization.

[0107] • Possibility of using small or large format printers.

[0108] • Low level of initial investment for implementation of the technique.

[0109] • High-productivity technical method for small and large runs.

[0110] • Digital printing with small or large format printers.

[0111] • System applicable to a wide range of textile substrates.

[0112] • Technological system, with a high level of automation and production standardization.

[0113] Although the above description defines the preferred embodiments of the present invention, said invention is not limited to these, but, on the contrary, it is also intended to include within the scope of this application all variations or modifications that are obvious to those skilled in the art and that do not affect or change the spirit of the invention.

Claims

CLAIMS 1. Digital transfer printing system on substrates CHARACTERIZED IN THAT it comprises: a transfer paper (1); inkjet digital printing inks (2); transparent base ink (3) and colored and effect powder adhesive (4), wherein the transfer paper includes a coating layer (12); wherein said paper (1) receives the CMYK (cyan, magenta, yellow and black) inkjet digital printing inks (2); simultaneously with the printing of a transparent base ink wherein the transparent base ink (3) forms a wet layer superimposed over the entire area of ​​the image, subsequently said wet layer receives the colored and effect powder adhesive (4) that when supplied with heat forms a cured film (34) on the printed image to be transferred to the substrate.

2. The digital transfer printing system on substrates of claim 1, characterized in that the printing order of the inks of the digital printing carried out on said paper (1) is managed in such a way that both the areas of the image in which the CMYK colors are printed, as well as the areas of this same image that are not printed with said CMYK inks, because they are reserved for the white color of the image or for the areas reserved so that their color or effect is provided by the colored and effect powder adhesive according to the design of the image that is printed.

3. The digital transfer printing system on substrates of the preceding claims, characterized in that the substrates are light or dark textiles.

4. The digital transfer printing system on substrates of the preceding claims, characterized in that the transfer paper (1) has a coated layer similar to digital printing inks, with components such as water-soluble polymers, fillers, resins or thermoplastic polymers, agglomerating polymers, release agents and preservatives.

5. The digital transfer printing system on substrates of the preceding claims, characterized in that the digital inkjet printing inks (2) comprise deionized water between 20% and 80% with a maximum conductivity of 75 microsiemens; organic pigments between 3% and 15% selected from the group: phthalocyanine, quinacridone pigments, mono azo pigments, diarylide pigments, pyrazolone pigments, dizaso condensation pigments, polycyclic pigments, which, in their dispersion have a particle size of less than 200 nanometers and preferably less than 80 nanometers; preservatives between 0.1% and 0.2% selected from the group of chloromethylisothiazolinone derivatives; Drying retardants between 5% and 30% selected from the group of water-soluble materials, such as ethylene glycol, 1,3-propanediol, and 1,4-butanediol. 1,4-cyclohexanedimethanol. 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol.1,2-propanediol, l-propane,2,3-triol, 1,2-butanediol, 1,3-butanediol. 2,3 butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol with weight. average molecular weight of 200, 300, 400, 600, 900, 1000, 1500 and 2000; and wetting agents between 1% and 5% selected from the group of: ethoxylated acetylene diols 2,5,8,11- Tetramethyl-6-dodecyl-5,8-diol ethoxylated; sulfosuccinates such as dioctyl sodium sulfosuccinate, sodium dibutyl sulfosuccinate, sodium diisopropyl sulfosuccinate; siloxane-based gemini surfactants; fluorinated surfactants, organosilicones; surfactants based on l-octylpyrrolidin-2-one pyrrolidones.

6. The digital transfer printing system on substrates of the preceding claims, characterized in that the transparent base ink (3) is a colorless water-based ink comprising: deionized water between 20% and 80% by weight; drying retarding agent between 10% and 40% by weight; pH stabilizer between 0.5% and 4% by weight; preservatives between 0.1% and 3% by weight; emulsifying agents between 0.5% and 4% by weight; wetting agents between 2% and 20% by weight; optical brightener between 0.5% and 3% by weight and plasticizers with concentrations that are between 5% and 40% by weight.

7. The digital transfer printing system on substrates of the preceding claims, characterized in that the deionized water that makes up the transparent base ink (3) of the present invention has a maximum conductivity of 75 microsiemens, wherein the drying retarding agents that make up said transparent base ink (3) are selected from the group of water-soluble materials, such as ethylene glycol; 1,3 propanediol; and 1,4 butanediol; 1,4 cyclohexanedimethanol; 1,5 pentanediol; 1,6 hexanediol; 1,8 octanediol; 1,2 propanediol; propane-1,2,3-triol; 1,2 butanediol; 1,3 butanediol; 2,3 butanediol; diethylene glycol; triethylene glycol; tetraethylene glycol; polyethylene glycol with an average molecular weight of 200, 300, 400, 600, 900, 1000, 1500 and 2000; the pH regulators that make up the transparent base ink (3) are selected from the group of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, triethanolamine,2-amino-2-methyl-l-propanol; diethanolamine; ethanolamine; the preservatives that make up the transparent base ink (3) are selected from the group of chloromethylisothiazolinone derivatives; the emulsifying agents that make up the transparent base ink (3) are selected from the group of non-ionic emulsifying agents such as: glycerol esters, such as glycerin monostearate and glyceryl stearate citrate, which form oil-in-water emulsions, also included are fatty alcohols of different degrees of ethoxylation, of 3,4,6, 8,10 ethylene oxide molecules such as lauryl alcohol ethoxylated with 10 ethylene oxide molecules, additionally polyglycerides, which are polymers of glycerin and fatty acids, they form oil-in-water and water-in-oil emulsions depending on the degree of polymerization, also included are alkanolamides of fatty acids that function as lauryl-diethanol amide, oleyl-diethanol amide,Also included are ethoxylated amines, ethoxylated amides, also included are anionic emulsifying agents among which are straight and branched chain sodium alkylbenzenesulfonates, straight and branched chain alkyl sulfates, and straight and branched chain alkyl ethoxy sulfates finally included are sucrose fatty acid esters, such as, sucrose polystearate; the wetting agents that make up the transparent base ink (3) are selected from the group of ethoxylated acetylene diols 2,5,8,11- Tetramethyl-6-dodecyl-5,8-diol ethoxylated; sulfosuccinates such as dioctyl sodium sulfosuccinate, sodium dibutyl sufosuccinate, sodium diisopropyl sulfosuccinate; siloxane-based gemini surfactants; fluorinated surfactants, organosilicones; surfactants based on l-octylpyrrolidin-2-one pyrrolidones; The optical brighteners or whiteners that make up the transparent base ink (3) are selected from the triazine-stilbene group such as 4,4 diamino 2,2 stilbene disulfonic acid, coumarins such as triazine phenyl coumarin, benzotriazole phenyl coumarin, naphthotriazole phenyl coumarin, bis benzoxazoles, imidazolines, diazoles, triazoles, biphenyl stilbenes.

8. The digital transfer printing system on substrates of the preceding claims, characterized in that the colored and effect powder adhesive (4) of the present invention comprises: thermofusible resins between 20% and 80% by weight; white covering pigments between 5% and 50% by weight; foaming agents between 1% and 5% by weight; mineral fillers between 1% and 20% by weight; plasticizers between 0.5% and 20% by weight; thermoplastic resins between 1% and 20% by weight; colored and special effect pigments between 3% and 30% by weight.

9. The digital transfer printing system on substrates of the preceding claims, characterized in that the thermofusible resins that make up the colored and effect powder adhesive (4) are selected from the group of ethylene vinyl acetate polymers, in block copolymers styrene isoprene styrene or styrene butadiene styrene, low density polyethylene, polyamides, ethylene acrylic copolymers, polypropylene, phenoxy resins, polyester, polyester amide, polyurethanes, butyl rubber, polyvinyl acetate and its copolymers and paraffin waxes; the white covering pigments that make up the colored and effect powder adhesive (4) are selected from the group of titanium dioxide in its crystalline forms of rutile and anatase, zinc oxide, lithopone, zinc sulfide and mixtures of barium sulfate and zinc sulfide;the blowing agents that make up the colored and effect powder adhesive (4) are selected from the group of hydrazines such as 4,4'-Oxybis (benzenesulfonylhydrazide), Diphenylsulfone 3,3 disulfohydrazide, Trihydrazinotriazine, semicarbazides such as P-toluylenesulfonyl semicarbazide, tetrazoles such as phenyltetrazoles, expandable polymeric microspheres, Benzoxazines such as isatoic anhydride and azodicarbonamide; the mineral fillers that make up the colored and effect powder adhesive (4) are selected from the group of calcined or hydrated aluminum silicate (kaolin), natural or synthetic calcium carbonate, talc, silicates, mica, pyrogenic silicas, microcrystalline silica, diatomaceous silica, synthetic silicas, where the mineral fillers must have average diameters between 5 and 20 microns;the plasticizers that make up the colored and effect powder adhesive (4) are selected from the group of: o Solids: neopentyl glycol dibenzoate, glyceryl tribenzoate, 1,4-cyclohexane dimethanol dibenzoate. o Liquids: dibutyl adipate, dibutoxyethyl adipate, di(2ethylhexyl) adipate, diisooctyl adipate, diisodecyl adipate, dibutyl sebacate, butyl benzyl adipate, dioctyl sebacate; Likewise, esters of citric acids such as triethyl citrate, tributyl citrate, acetyl tri (n-butyl) citrate, acetyl tri (n-hexyl) citrate can be selected. Esters of alkylsulfonic acids with phenols, benzoates such as propylene glycol dibenzoate, dipropylene glycol dibenzoate, terepthalates such as Di 2 ethylhexyl phthalate (DOTP), trimellitates such as tri 2 ethylhexyl trimellitate (TOTM), triisooctyl trimellitate (TIOTM), triisononyl trimellitate (TINTM) also work; the thermoplastic resins that make up the colored and effect powder adhesive (4) are selected from the group of polyvinyl chloride, acrylics, polyethylene, polypropylene, polyester and polycarbonate; The coloured and special effect pigments that make up the coloured and effect powder adhesive (4) are selected from the group of organic pigments based on phthalocyanines, benzidines, mirellas, phosphorescent pigments, fluorescent pigments, metallic pigments (gold, silver, etc.)), pearlescent pigments, and migration control agents.

10. Digital transfer printing process on light or dark textile substrates CHARACTERIZED IN THAT it comprises the following stages: a. Printing of the image on the transfer paper (1), by means of a piezoelectric head printer loaded with digital printing inks (CMYK) inkjet (2) and transparent base ink (3). b. Once the print leaves the printer, the colored and effects powder adhesive (4) is applied to the newly printed wet image. c. The image coated with the colored and effects powder adhesive (4) is cured by supplying heat in an oven or with a heat gun between 160°C and 180°C for between 10 and 40 seconds. The white color of the image or special effect is obtained with the addition of the colored and effects powder adhesive. d.The transfer paper from the previous paragraph is placed on the substrate where it will be transferred and is subjected to thermal pressing between 150°C and 200°C for 10-20 seconds at a pressure between 2.1 and 6.3 kgf / cm2 (30 to 90 Lbf / in. 2 ).

11. Digital transfer printing process on light or dark textile substrates according to claim 12, characterized in that, after step d. a step is included: e. The garment or substrate is removed and allowed to cool; and a step is included: f. The transfer paper is removed to view the image transferred to the substrate.

12. Digital transfer printing process on light or dark textile substrates according to claims 10 and 11, characterized in that it includes raster image processing printing software, which manages the quantity and printing mode of the inks.

13. Digital transfer printing process on light or dark textile substrates according to claims 10 to 12, characterized in that, in literal a. the image is printed in mirror mode, where, as the CMYK colors are printed, the transparent base ink (3) is printed forming a translucent and shiny layer on the image, where the transparent base ink, in addition to covering the areas of the image that are printed with the CMYK digital printing inks, is also printed in the areas corresponding to the white color of the image or reserved so that its color or effect is provided by the colored and effect powder adhesive according to the design of the image that is printed.

14. Digital transfer printing process on light or dark textile substrates according to claims 10 to 13, characterized in that, in literal b. the colored and effect powder adhesive (4) is retained by the wet layer printed with transparent base ink, where once the colored and effect powder adhesive (4) has been applied, the excess is removed.

15. Digital transfer printing process on light or dark textile substrates according to claims 10 to 14, characterized in that, in literal b. after 15 to 20 seconds have elapsed since the application of the colored and effect powder adhesive (4), the powder adhesive that did not come into contact with the image must be removed by mechanical or manual vibration of the printed paper while it is in a vertical position or by suction with the paper in a horizontal position.

16. Digital transfer printing process on light or dark textile substrates according to claims 10 to 15, characterized in that, in literal d. the transfer paper of literal c. is placed on the substrate where it will be transferred and is subjected to thermal pressing in a calender at 160°C for 15 seconds at a pressure of 4.2 kgf / cm2.

17. Digital transfer printing process on light or dark textile substrates according to claims 10 to 16, characterized in that, in one embodiment, the printer with piezoelectric heads has at least 6 injection channels, where 4 channels are intended for the injection of CMYK inkjet digital printing inks (2), and 2 channels are intended for the injection of transparent base ink (3).

Images